Organosilicon compounds are employed in building protection because of their outstanding impregnating action, their water and dirt repellency, their environmental-friendliness and their physiological acceptability. For a composition to perform effectively as a wood preservative it is essential that there be rapid and deep penetration. DE-A-3 900 303 describes the impregnation of wood with an aqueous solution of propyltrimethoxysilane. U.S. Pat. No. 5,073,195 describes the treatment of wood with an aqueous solution of a water-soluble silane coupling agent and an alkyltri-alkoxysilane. However, these aqueous solutions do not have a long storage life since there is rapid formation of water-insoluble condensation products which hardly penetrate into the wood subsequently.
German patent application P 42 41 727 of Dec. 10, 1992, describes organopolysiloxane-containing compositions which are self-dispersing in water and comprise
(A) a salt of an organic or inorganic acid and an organopolysiloxane which contains SiC-bonded radicals with basic nitrogen in amounts of at least 0.5% by weight of basic nitrogen, based on the weight of this organopolysiloxane, PA1 (B) a solid which is soluble in water at 20.degree. C. under 1020 hPa to the extent of at most one part by weight in 100 parts by weight, excluding organosilicon compounds which are solid at 20.degree. C. under 1020 hPa and dissolve under these conditions to the extent of more than 50 parts by weight in 100 parts by weight (A), optionally mixed with PA1 (C) an organosilicon compound containing basic nitrogen in amounts of 0% to 0.5% by weight, based on the weight of this organosilicon compound, PA1 (A) a salt of an organic or inorganic acid and an organopolysiloxane which contains SiC-bonded radicals with basic nitrogen in amounts of at least 0.5% by weight of basic nitrogen, based on the weight of this organopolysiloxane, PA1 (B) a water-repellent active compound which is not solid at 20.degree. C. under 1020 hPa, with the proviso that the water-repellent active compound can also be an organosilicon compound which is solid at 20.degree. C. under 1020 hPa and dissolves under these conditions to the extent of more than 50 parts by weight in 100 parts by weight of (A), optionally mixed with an organosilicon compound containing basic nitrogen in amounts of 0% to 0.5% by weight, based on the weight of this organosilicon compound, and/or silicic acid esters, and PA1 (c) water. PA1 R.sup.1 can be identical or different and represents monovalent, SiC-bonded radicals containing basic nitrogen, PA1 R.sup.2 can be identical or different and represents a hydrogen atom or monovalent organic radicals, PA1 a is 0, 1, 2 or 3, PA1 b is 0, 1, 2 or 3 and PA1 c is 0, 1, 2 or 3, PA1 R.sup.6 can be identical or different and represents a hydrogen atom or monovalent organic radicals, PA1 d is 0, 1, 2, 3 or 4 and PA1 is 0, 1, 2, 3 or 4,
and the treatment of wood with these compositions.